As is well known in the art, an inner diameter of a shell of a grinding mill typically is lined with a mill liner, for wear protection, i.e., to protect the shell. The mill liner may include, for instance, shell plates positioned on the inner diameter so as to substantially cover the shell's inner diameter, and lifter bars spaced apart from each other, with the shell plates positioned between the lifter bars and the shell. The heads of bolts extending through the shell are held in the lifter bars respectively, so that tightening nuts on the portions of the bolts extending outside the shell urges the lifter bars against the shell plates and ultimately the shell, for securing the lifter bars and shell plates to the shell. The lifter bars are positioned to press onto portions of the shell plates, to hold the shell plates against the inner diameter. As is known, the shell plates and the lifter bars typically are made of various materials, for instance, the shell plates may be made of steel and/or a rubber or rubber-like material, and the lifter bars may be made of steel, and/or rubber or rubber-like material.
Typically, once the mill liner has become worn to a certain extent, all or part of the mill liner is replaced. Often, only a part of the mill liner is to be replaced. For instance, the lifter bars may have a substantially shorter useful life than the shell plates on which the lifter bar is at least partially positioned. In this situation, when the lifter bars have become worn, it is sometimes intended to replace only the lifter bars, i.e., where the shell plates still have a substantial portion of their useful life remaining. However, in practice, removal of the lifter bars alone (i.e., without removing some or all of the shell plates) is usually very difficult. This is because each lifter bar, and the shell plates with which the lifter bar is engaged, tend to become relatively securely fused or bonded to each other over time. It appears that the mechanism which results in parts of the mill liner adhering together after use over a period of time has not been studied in detail. It is thought that, where the fused elements include one or more elastomeric materials, the elements tend to adhere together over time due to compression set.